1. Field of the Invention
This invention relates generally to semiconductor processing, and more particularly to scribe structures and methods of making the same for semiconductor chips.
2. Description of the Related Art
Semiconductor chips or dice are typically manufactured en masse as part of a semiconductor wafer. Selected portions of the semiconductor wafer are set aside for each of the dice, and at an appropriate point in the process flow, the semiconductor dice are singulated from the wafer by some form of cutting process. In various conventional techniques, the cutting process is performed by mechanical sawing or laser scribing. These techniques may be used to completely cleave the semiconductor dice from the wafer, or to establish grooves as a precursor to a mechanical breaking process. In order to protect the individual dice from damage that may occur during the dicing operation, the dice are segregated laterally from each other by so-called dicing streets, which are merely portions of the semiconductor wafer in which no active circuit structures are formed. Further protection is provided by way of a scribe line structure that surrounds each semiconductor die.
A typical conventional scribe line structure consists of a frame-like structure that, when viewed from above, resembles a rectangular fortress wall. The scribe structure is fabricated around the active device region of the semiconductor die. In the conventional form, there is typically a gap between the active region and, in particular, the corners of the active region and the interior corners of the rectangular scribe structure.
The dicing process, despite advances in saw manufacture and laser cutting processes, is a thermo-mechanically stressful operation. During mechanical sawing, the dice undergo significant cyclic stresses and some heating. During laser scribing, the dice not only undergo significant thermal stresses that can, if high enough, even ablate portions of the scribe structure. Multiple heating cycles occur due horizontal and vertical dicing across a given die corner. It turns out that the corners of the semiconductor dice are particularly susceptible to both thermal shocks and mechanical stresses. By definition, corners create stress risers that are less resilient to mechanical stresses then other portions. Cracks or other types of damage created at the corners of the semiconductor dice can, if not checked, propagate inward and potentially damage the delicate circuit structures within the active region.
The present invention is directed to overcoming or reducing the effects of one or more of the foregoing disadvantages.